Bone and soft tissue infections

Question 1

Which organism is most commonly a cause of osteomyelitis?

Answer 1

Staph aureus

Question 2

Give six special cases of acute osteomyelitis and the most likely causative organism

Answer 2

Diabetic foot - mixed incl. anaerobes
Pressure sores - mixed
Vertebral osteomyelitis - S. aureus, TB
Sternal osteomyelitis - coag -ve staph post cardiac surgery
Sickle cell disease - salmonella
STD - gonococcus

Question 3

Give three sources of infection in osteomyelitis

Answer 3

Haematogenous spread
Contiguous (local) spread
Secondary to vascular insufficiency

Question 4

Define sequestrum

Answer 4

Necrotic bone that has become detached from healthy bone

Question 5

Define involucrum

Answer 5

a layer of new bone growth outside existing bone; often surrounds the sequestrum

Question 6

What is the difference between acute and chronic osteomyelitis (other than time)?

Answer 6

Acute osteomyelitis also presents with constitutional symptoms, whereas these are rarely present in chronic disease.

Question 7

Give a red flag for osteomyelitis in adults (particularly vertebral)

Answer 7

Bone pain (e.g. back pain) that keeps them awake at night

Question 8

What is the best investigation for osteomyelitis

Answer 8

MRI

Question 9

How useful are X-rays in diagnosing osteomyelitis?

Answer 9

Useful in subacute/chronic cases but less so in acute; x-rays are often normal in the first two weeks of infection

Question 10

Give six potential complications of osteomyelitis

Answer 10

Septicaemia (and death)
Metastatic infection
Pathological fracture
Septic arthritis
Altered bone growth
Chronic osteomyelitis